Pileus Git - ~andy/linux/blob - drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  * Copyright (c) 2006 Nokia Corporation
   6  * Various changes: Imre Deak <imre.deak@nokia.com>
   7  *
   8  * Using code from:
   9  *  - corgi_ts.c
  10  *      Copyright (C) 2004-2005 Richard Purdie
  11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  12  *      Copyright (C) 2002 MontaVista Software
  13  *      Copyright (C) 2004 Texas Instruments
  14  *      Copyright (C) 2005 Dirk Behme
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2 as
  18  *  published by the Free Software Foundation.
  19  */
  20 #include <linux/types.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/init.h>
  23 #include <linux/err.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/input.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/slab.h>
  29 #include <linux/pm.h>
  30 #include <linux/gpio.h>
  31 #include <linux/spi/spi.h>
  32 #include <linux/spi/ads7846.h>
  33 #include <linux/regulator/consumer.h>
  34 #include <linux/module.h>
  35 #include <asm/irq.h>
  36
  37 /*
  38  * This code has been heavily tested on a Nokia 770, and lightly
  39  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  40  * TSC2046 is just newer ads7846 silicon.
  41  * Support for ads7843 tested on Atmel at91sam926x-EK.
  42  * Support for ads7845 has only been stubbed in.
  43  * Support for Analog Devices AD7873 and AD7843 tested.
  44  *
  45  * IRQ handling needs a workaround because of a shortcoming in handling
  46  * edge triggered IRQs on some platforms like the OMAP1/2. These
  47  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  48  * have to maintain our own SW IRQ disabled status. This should be
  49  * removed as soon as the affected platform's IRQ handling is fixed.
  50  *
  51  * App note sbaa036 talks in more detail about accurate sampling...
  52  * that ought to help in situations like LCDs inducing noise (which
  53  * can also be helped by using synch signals) and more generally.
  54  * This driver tries to utilize the measures described in the app
  55  * note. The strength of filtering can be set in the board-* specific
  56  * files.
  57  */
  58
  59 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
  60 #define TS_POLL_PERIOD  5       /* ms delay between samples */
  61
  62 /* this driver doesn't aim at the peak continuous sample rate */
  63 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  64
  65 struct ts_event {
  66         /*
  67          * For portability, we can't read 12 bit values using SPI (which
  68          * would make the controller deliver them as native byte order u16
  69          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  70          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  71          */
  72         u16     x;
  73         u16     y;
  74         u16     z1, z2;
  75         bool    ignore;
  76         u8      x_buf[3];
  77         u8      y_buf[3];
  78 };
  79
  80 /*
  81  * We allocate this separately to avoid cache line sharing issues when
  82  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  83  * systems where main memory is not DMA-coherent (most non-x86 boards).
  84  */
  85 struct ads7846_packet {
  86         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  87         u16                     dummy;          /* for the pwrdown read */
  88         struct ts_event         tc;
  89         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  90         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  91 };
  92
  93 struct ads7846 {
  94         struct input_dev        *input;
  95         char                    phys[32];
  96         char                    name[32];
  97
  98         struct spi_device       *spi;
  99         struct regulator        *reg;
 100
 101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 102         struct attribute_group  *attr_group;
 103         struct device           *hwmon;
 104 #endif
 105
 106         u16                     model;
 107         u16                     vref_mv;
 108         u16                     vref_delay_usecs;
 109         u16                     x_plate_ohms;
 110         u16                     pressure_max;
 111
 112         bool                    swap_xy;
 113         bool                    use_internal;
 114
 115         struct ads7846_packet   *packet;
 116
 117         struct spi_transfer     xfer[18];
 118         struct spi_message      msg[5];
 119         int                     msg_count;
 120         wait_queue_head_t       wait;
 121
 122         bool                    pendown;
 123
 124         int                     read_cnt;
 125         int                     read_rep;
 126         int                     last_read;
 127
 128         u16                     debounce_max;
 129         u16                     debounce_tol;
 130         u16                     debounce_rep;
 131
 132         u16                     penirq_recheck_delay_usecs;
 133
 134         struct mutex            lock;
 135         bool                    stopped;        /* P: lock */
 136         bool                    disabled;       /* P: lock */
 137         bool                    suspended;      /* P: lock */
 138
 139         int                     (*filter)(void *data, int data_idx, int *val);
 140         void                    *filter_data;
 141         void                    (*filter_cleanup)(void *data);
 142         int                     (*get_pendown_state)(void);
 143         int                     gpio_pendown;
 144
 145         void                    (*wait_for_sync)(void);
 146 };
 147
 148 /* leave chip selected when we're done, for quicker re-select? */
 149 #if     0
 150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 151 #else
 152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 153 #endif
 154
 155 /*--------------------------------------------------------------------------*/
 156
 157 /* The ADS7846 has touchscreen and other sensors.
 158  * Earlier ads784x chips are somewhat compatible.
 159  */
 160 #define ADS_START               (1 << 7)
 161 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 162 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 163 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 164 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 165 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 166 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 167 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 168 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 169 #define ADS_8_BIT               (1 << 3)
 170 #define ADS_12_BIT              (0 << 3)
 171 #define ADS_SER                 (1 << 2)        /* non-differential */
 172 #define ADS_DFR                 (0 << 2)        /* differential */
 173 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 174 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 175 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 176 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 177
 178 #define MAX_12BIT       ((1<<12)-1)
 179
 180 /* leave ADC powered up (disables penirq) between differential samples */
 181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 182         | ADS_12_BIT | ADS_DFR | \
 183         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 184
 185 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 186 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 187 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 188
 189 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 190 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 191
 192 /* single-ended samples need to first power up reference voltage;
 193  * we leave both ADC and VREF powered
 194  */
 195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 196         | ADS_12_BIT | ADS_SER)
 197
 198 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 200
 201 /* Must be called with ts->lock held */
 202 static void ads7846_stop(struct ads7846 *ts)
 203 {
 204         if (!ts->disabled && !ts->suspended) {
 205                 /* Signal IRQ thread to stop polling and disable the handler. */
 206                 ts->stopped = true;
 207                 mb();
 208                 wake_up(&ts->wait);
 209                 disable_irq(ts->spi->irq);
 210         }
 211 }
 212
 213 /* Must be called with ts->lock held */
 214 static void ads7846_restart(struct ads7846 *ts)
 215 {
 216         if (!ts->disabled && !ts->suspended) {
 217                 /* Tell IRQ thread that it may poll the device. */
 218                 ts->stopped = false;
 219                 mb();
 220                 enable_irq(ts->spi->irq);
 221         }
 222 }
 223
 224 /* Must be called with ts->lock held */
 225 static void __ads7846_disable(struct ads7846 *ts)
 226 {
 227         ads7846_stop(ts);
 228         regulator_disable(ts->reg);
 229
 230         /*
 231          * We know the chip's in low power mode since we always
 232          * leave it that way after every request
 233          */
 234 }
 235
 236 /* Must be called with ts->lock held */
 237 static void __ads7846_enable(struct ads7846 *ts)
 238 {
 239         int error;
 240
 241         error = regulator_enable(ts->reg);
 242         if (error != 0)
 243                 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
 244
 245         ads7846_restart(ts);
 246 }
 247
 248 static void ads7846_disable(struct ads7846 *ts)
 249 {
 250         mutex_lock(&ts->lock);
 251
 252         if (!ts->disabled) {
 253
 254                 if  (!ts->suspended)
 255                         __ads7846_disable(ts);
 256
 257                 ts->disabled = true;
 258         }
 259
 260         mutex_unlock(&ts->lock);
 261 }
 262
 263 static void ads7846_enable(struct ads7846 *ts)
 264 {
 265         mutex_lock(&ts->lock);
 266
 267         if (ts->disabled) {
 268
 269                 ts->disabled = false;
 270
 271                 if (!ts->suspended)
 272                         __ads7846_enable(ts);
 273         }
 274
 275         mutex_unlock(&ts->lock);
 276 }
 277
 278 /*--------------------------------------------------------------------------*/
 279
 280 /*
 281  * Non-touchscreen sensors only use single-ended conversions.
 282  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 283  * ads7846 lets that pin be unconnected, to use internal vREF.
 284  */
 285
 286 struct ser_req {
 287         u8                      ref_on;
 288         u8                      command;
 289         u8                      ref_off;
 290         u16                     scratch;
 291         struct spi_message      msg;
 292         struct spi_transfer     xfer[6];
 293         /*
 294          * DMA (thus cache coherency maintenance) requires the
 295          * transfer buffers to live in their own cache lines.
 296          */
 297         __be16 sample ____cacheline_aligned;
 298 };
 299
 300 struct ads7845_ser_req {
 301         u8                      command[3];
 302         struct spi_message      msg;
 303         struct spi_transfer     xfer[2];
 304         /*
 305          * DMA (thus cache coherency maintenance) requires the
 306          * transfer buffers to live in their own cache lines.
 307          */
 308         u8 sample[3] ____cacheline_aligned;
 309 };
 310
 311 static int ads7846_read12_ser(struct device *dev, unsigned command)
 312 {
 313         struct spi_device *spi = to_spi_device(dev);
 314         struct ads7846 *ts = dev_get_drvdata(dev);
 315         struct ser_req *req;
 316         int status;
 317
 318         req = kzalloc(sizeof *req, GFP_KERNEL);
 319         if (!req)
 320                 return -ENOMEM;
 321
 322         spi_message_init(&req->msg);
 323
 324         /* maybe turn on internal vREF, and let it settle */
 325         if (ts->use_internal) {
 326                 req->ref_on = REF_ON;
 327                 req->xfer[0].tx_buf = &req->ref_on;
 328                 req->xfer[0].len = 1;
 329                 spi_message_add_tail(&req->xfer[0], &req->msg);
 330
 331                 req->xfer[1].rx_buf = &req->scratch;
 332                 req->xfer[1].len = 2;
 333
 334                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 335                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 336                 spi_message_add_tail(&req->xfer[1], &req->msg);
 337
 338                 /* Enable reference voltage */
 339                 command |= ADS_PD10_REF_ON;
 340         }
 341
 342         /* Enable ADC in every case */
 343         command |= ADS_PD10_ADC_ON;
 344
 345         /* take sample */
 346         req->command = (u8) command;
 347         req->xfer[2].tx_buf = &req->command;
 348         req->xfer[2].len = 1;
 349         spi_message_add_tail(&req->xfer[2], &req->msg);
 350
 351         req->xfer[3].rx_buf = &req->sample;
 352         req->xfer[3].len = 2;
 353         spi_message_add_tail(&req->xfer[3], &req->msg);
 354
 355         /* REVISIT:  take a few more samples, and compare ... */
 356
 357         /* converter in low power mode & enable PENIRQ */
 358         req->ref_off = PWRDOWN;
 359         req->xfer[4].tx_buf = &req->ref_off;
 360         req->xfer[4].len = 1;
 361         spi_message_add_tail(&req->xfer[4], &req->msg);
 362
 363         req->xfer[5].rx_buf = &req->scratch;
 364         req->xfer[5].len = 2;
 365         CS_CHANGE(req->xfer[5]);
 366         spi_message_add_tail(&req->xfer[5], &req->msg);
 367
 368         mutex_lock(&ts->lock);
 369         ads7846_stop(ts);
 370         status = spi_sync(spi, &req->msg);
 371         ads7846_restart(ts);
 372         mutex_unlock(&ts->lock);
 373
 374         if (status == 0) {
 375                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 376                 status = be16_to_cpu(req->sample);
 377                 status = status >> 3;
 378                 status &= 0x0fff;
 379         }
 380
 381         kfree(req);
 382         return status;
 383 }
 384
 385 static int ads7845_read12_ser(struct device *dev, unsigned command)
 386 {
 387         struct spi_device *spi = to_spi_device(dev);
 388         struct ads7846 *ts = dev_get_drvdata(dev);
 389         struct ads7845_ser_req *req;
 390         int status;
 391
 392         req = kzalloc(sizeof *req, GFP_KERNEL);
 393         if (!req)
 394                 return -ENOMEM;
 395
 396         spi_message_init(&req->msg);
 397
 398         req->command[0] = (u8) command;
 399         req->xfer[0].tx_buf = req->command;
 400         req->xfer[0].rx_buf = req->sample;
 401         req->xfer[0].len = 3;
 402         spi_message_add_tail(&req->xfer[0], &req->msg);
 403
 404         mutex_lock(&ts->lock);
 405         ads7846_stop(ts);
 406         status = spi_sync(spi, &req->msg);
 407         ads7846_restart(ts);
 408         mutex_unlock(&ts->lock);
 409
 410         if (status == 0) {
 411                 /* BE12 value, then padding */
 412                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 413                 status = status >> 3;
 414                 status &= 0x0fff;
 415         }
 416
 417         kfree(req);
 418         return status;
 419 }
 420
 421 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 422
 423 #define SHOW(name, var, adjust) static ssize_t \
 424 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 425 { \
 426         struct ads7846 *ts = dev_get_drvdata(dev); \
 427         ssize_t v = ads7846_read12_ser(dev, \
 428                         READ_12BIT_SER(var)); \
 429         if (v < 0) \
 430                 return v; \
 431         return sprintf(buf, "%u\n", adjust(ts, v)); \
 432 } \
 433 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 434
 435
 436 /* Sysfs conventions report temperatures in millidegrees Celsius.
 437  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 438  * accuracy scheme without calibration data.  For now we won't try either;
 439  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 440  */
 441 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 442 {
 443         return v;
 444 }
 445
 446 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 447 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 448
 449
 450 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 451  * if we know vREF.  userspace may need to scale vAUX to match the board's
 452  * external resistors; we assume that vBATT only uses the internal ones.
 453  */
 454 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 455 {
 456         unsigned retval = v;
 457
 458         /* external resistors may scale vAUX into 0..vREF */
 459         retval *= ts->vref_mv;
 460         retval = retval >> 12;
 461
 462         return retval;
 463 }
 464
 465 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 466 {
 467         unsigned retval = vaux_adjust(ts, v);
 468
 469         /* ads7846 has a resistor ladder to scale this signal down */
 470         if (ts->model == 7846)
 471                 retval *= 4;
 472
 473         return retval;
 474 }
 475
 476 SHOW(in0_input, vaux, vaux_adjust)
 477 SHOW(in1_input, vbatt, vbatt_adjust)
 478
 479 static struct attribute *ads7846_attributes[] = {
 480         &dev_attr_temp0.attr,
 481         &dev_attr_temp1.attr,
 482         &dev_attr_in0_input.attr,
 483         &dev_attr_in1_input.attr,
 484         NULL,
 485 };
 486
 487 static struct attribute_group ads7846_attr_group = {
 488         .attrs = ads7846_attributes,
 489 };
 490
 491 static struct attribute *ads7843_attributes[] = {
 492         &dev_attr_in0_input.attr,
 493         &dev_attr_in1_input.attr,
 494         NULL,
 495 };
 496
 497 static struct attribute_group ads7843_attr_group = {
 498         .attrs = ads7843_attributes,
 499 };
 500
 501 static struct attribute *ads7845_attributes[] = {
 502         &dev_attr_in0_input.attr,
 503         NULL,
 504 };
 505
 506 static struct attribute_group ads7845_attr_group = {
 507         .attrs = ads7845_attributes,
 508 };
 509
 510 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 511 {
 512         struct device *hwmon;
 513         int err;
 514
 515         /* hwmon sensors need a reference voltage */
 516         switch (ts->model) {
 517         case 7846:
 518                 if (!ts->vref_mv) {
 519                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 520                         ts->vref_mv = 2500;
 521                         ts->use_internal = true;
 522                 }
 523                 break;
 524         case 7845:
 525         case 7843:
 526                 if (!ts->vref_mv) {
 527                         dev_warn(&spi->dev,
 528                                 "external vREF for ADS%d not specified\n",
 529                                 ts->model);
 530                         return 0;
 531                 }
 532                 break;
 533         }
 534
 535         /* different chips have different sensor groups */
 536         switch (ts->model) {
 537         case 7846:
 538                 ts->attr_group = &ads7846_attr_group;
 539                 break;
 540         case 7845:
 541                 ts->attr_group = &ads7845_attr_group;
 542                 break;
 543         case 7843:
 544                 ts->attr_group = &ads7843_attr_group;
 545                 break;
 546         default:
 547                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 548                 return 0;
 549         }
 550
 551         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 552         if (err)
 553                 return err;
 554
 555         hwmon = hwmon_device_register(&spi->dev);
 556         if (IS_ERR(hwmon)) {
 557                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 558                 return PTR_ERR(hwmon);
 559         }
 560
 561         ts->hwmon = hwmon;
 562         return 0;
 563 }
 564
 565 static void ads784x_hwmon_unregister(struct spi_device *spi,
 566                                      struct ads7846 *ts)
 567 {
 568         if (ts->hwmon) {
 569                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 570                 hwmon_device_unregister(ts->hwmon);
 571         }
 572 }
 573
 574 #else
 575 static inline int ads784x_hwmon_register(struct spi_device *spi,
 576                                          struct ads7846 *ts)
 577 {
 578         return 0;
 579 }
 580
 581 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 582                                             struct ads7846 *ts)
 583 {
 584 }
 585 #endif
 586
 587 static ssize_t ads7846_pen_down_show(struct device *dev,
 588                                      struct device_attribute *attr, char *buf)
 589 {
 590         struct ads7846 *ts = dev_get_drvdata(dev);
 591
 592         return sprintf(buf, "%u\n", ts->pendown);
 593 }
 594
 595 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 596
 597 static ssize_t ads7846_disable_show(struct device *dev,
 598                                      struct device_attribute *attr, char *buf)
 599 {
 600         struct ads7846 *ts = dev_get_drvdata(dev);
 601
 602         return sprintf(buf, "%u\n", ts->disabled);
 603 }
 604
 605 static ssize_t ads7846_disable_store(struct device *dev,
 606                                      struct device_attribute *attr,
 607                                      const char *buf, size_t count)
 608 {
 609         struct ads7846 *ts = dev_get_drvdata(dev);
 610         unsigned int i;
 611         int err;
 612
 613         err = kstrtouint(buf, 10, &i);
 614         if (err)
 615                 return err;
 616
 617         if (i)
 618                 ads7846_disable(ts);
 619         else
 620                 ads7846_enable(ts);
 621
 622         return count;
 623 }
 624
 625 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 626
 627 static struct attribute *ads784x_attributes[] = {
 628         &dev_attr_pen_down.attr,
 629         &dev_attr_disable.attr,
 630         NULL,
 631 };
 632
 633 static struct attribute_group ads784x_attr_group = {
 634         .attrs = ads784x_attributes,
 635 };
 636
 637 /*--------------------------------------------------------------------------*/
 638
 639 static int get_pendown_state(struct ads7846 *ts)
 640 {
 641         if (ts->get_pendown_state)
 642                 return ts->get_pendown_state();
 643
 644         return !gpio_get_value(ts->gpio_pendown);
 645 }
 646
 647 static void null_wait_for_sync(void)
 648 {
 649 }
 650
 651 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 652 {
 653         struct ads7846 *ts = ads;
 654
 655         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 656                 /* Start over collecting consistent readings. */
 657                 ts->read_rep = 0;
 658                 /*
 659                  * Repeat it, if this was the first read or the read
 660                  * wasn't consistent enough.
 661                  */
 662                 if (ts->read_cnt < ts->debounce_max) {
 663                         ts->last_read = *val;
 664                         ts->read_cnt++;
 665                         return ADS7846_FILTER_REPEAT;
 666                 } else {
 667                         /*
 668                          * Maximum number of debouncing reached and still
 669                          * not enough number of consistent readings. Abort
 670                          * the whole sample, repeat it in the next sampling
 671                          * period.
 672                          */
 673                         ts->read_cnt = 0;
 674                         return ADS7846_FILTER_IGNORE;
 675                 }
 676         } else {
 677                 if (++ts->read_rep > ts->debounce_rep) {
 678                         /*
 679                          * Got a good reading for this coordinate,
 680                          * go for the next one.
 681                          */
 682                         ts->read_cnt = 0;
 683                         ts->read_rep = 0;
 684                         return ADS7846_FILTER_OK;
 685                 } else {
 686                         /* Read more values that are consistent. */
 687                         ts->read_cnt++;
 688                         return ADS7846_FILTER_REPEAT;
 689                 }
 690         }
 691 }
 692
 693 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 694 {
 695         return ADS7846_FILTER_OK;
 696 }
 697
 698 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 699 {
 700         struct spi_transfer *t =
 701                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 702
 703         if (ts->model == 7845) {
 704                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 705         } else {
 706                 /*
 707                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 708                  * padding; built from two 8 bit values written msb-first.
 709                  */
 710                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 711         }
 712 }
 713
 714 static void ads7846_update_value(struct spi_message *m, int val)
 715 {
 716         struct spi_transfer *t =
 717                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 718
 719         *(u16 *)t->rx_buf = val;
 720 }
 721
 722 static void ads7846_read_state(struct ads7846 *ts)
 723 {
 724         struct ads7846_packet *packet = ts->packet;
 725         struct spi_message *m;
 726         int msg_idx = 0;
 727         int val;
 728         int action;
 729         int error;
 730
 731         while (msg_idx < ts->msg_count) {
 732
 733                 ts->wait_for_sync();
 734
 735                 m = &ts->msg[msg_idx];
 736                 error = spi_sync(ts->spi, m);
 737                 if (error) {
 738                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
 739                         packet->tc.ignore = true;
 740                         return;
 741                 }
 742
 743                 /*
 744                  * Last message is power down request, no need to convert
 745                  * or filter the value.
 746                  */
 747                 if (msg_idx < ts->msg_count - 1) {
 748
 749                         val = ads7846_get_value(ts, m);
 750
 751                         action = ts->filter(ts->filter_data, msg_idx, &val);
 752                         switch (action) {
 753                         case ADS7846_FILTER_REPEAT:
 754                                 continue;
 755
 756                         case ADS7846_FILTER_IGNORE:
 757                                 packet->tc.ignore = true;
 758                                 msg_idx = ts->msg_count - 1;
 759                                 continue;
 760
 761                         case ADS7846_FILTER_OK:
 762                                 ads7846_update_value(m, val);
 763                                 packet->tc.ignore = false;
 764                                 msg_idx++;
 765                                 break;
 766
 767                         default:
 768                                 BUG();
 769                         }
 770                 } else {
 771                         msg_idx++;
 772                 }
 773         }
 774 }
 775
 776 static void ads7846_report_state(struct ads7846 *ts)
 777 {
 778         struct ads7846_packet *packet = ts->packet;
 779         unsigned int Rt;
 780         u16 x, y, z1, z2;
 781
 782         /*
 783          * ads7846_get_value() does in-place conversion (including byte swap)
 784          * from on-the-wire format as part of debouncing to get stable
 785          * readings.
 786          */
 787         if (ts->model == 7845) {
 788                 x = *(u16 *)packet->tc.x_buf;
 789                 y = *(u16 *)packet->tc.y_buf;
 790                 z1 = 0;
 791                 z2 = 0;
 792         } else {
 793                 x = packet->tc.x;
 794                 y = packet->tc.y;
 795                 z1 = packet->tc.z1;
 796                 z2 = packet->tc.z2;
 797         }
 798
 799         /* range filtering */
 800         if (x == MAX_12BIT)
 801                 x = 0;
 802
 803         if (ts->model == 7843) {
 804                 Rt = ts->pressure_max / 2;
 805         } else if (ts->model == 7845) {
 806                 if (get_pendown_state(ts))
 807                         Rt = ts->pressure_max / 2;
 808                 else
 809                         Rt = 0;
 810                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 811         } else if (likely(x && z1)) {
 812                 /* compute touch pressure resistance using equation #2 */
 813                 Rt = z2;
 814                 Rt -= z1;
 815                 Rt *= x;
 816                 Rt *= ts->x_plate_ohms;
 817                 Rt /= z1;
 818                 Rt = (Rt + 2047) >> 12;
 819         } else {
 820                 Rt = 0;
 821         }
 822
 823         /*
 824          * Sample found inconsistent by debouncing or pressure is beyond
 825          * the maximum. Don't report it to user space, repeat at least
 826          * once more the measurement
 827          */
 828         if (packet->tc.ignore || Rt > ts->pressure_max) {
 829                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 830                          packet->tc.ignore, Rt);
 831                 return;
 832         }
 833
 834         /*
 835          * Maybe check the pendown state before reporting. This discards
 836          * false readings when the pen is lifted.
 837          */
 838         if (ts->penirq_recheck_delay_usecs) {
 839                 udelay(ts->penirq_recheck_delay_usecs);
 840                 if (!get_pendown_state(ts))
 841                         Rt = 0;
 842         }
 843
 844         /*
 845          * NOTE: We can't rely on the pressure to determine the pen down
 846          * state, even this controller has a pressure sensor. The pressure
 847          * value can fluctuate for quite a while after lifting the pen and
 848          * in some cases may not even settle at the expected value.
 849          *
 850          * The only safe way to check for the pen up condition is in the
 851          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 852          */
 853         if (Rt) {
 854                 struct input_dev *input = ts->input;
 855
 856                 if (ts->swap_xy)
 857                         swap(x, y);
 858
 859                 if (!ts->pendown) {
 860                         input_report_key(input, BTN_TOUCH, 1);
 861                         ts->pendown = true;
 862                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 863                 }
 864
 865                 input_report_abs(input, ABS_X, x);
 866                 input_report_abs(input, ABS_Y, y);
 867                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 868
 869                 input_sync(input);
 870                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 871         }
 872 }
 873
 874 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 875 {
 876         struct ads7846 *ts = handle;
 877
 878         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 879 }
 880
 881
 882 static irqreturn_t ads7846_irq(int irq, void *handle)
 883 {
 884         struct ads7846 *ts = handle;
 885
 886         /* Start with a small delay before checking pendown state */
 887         msleep(TS_POLL_DELAY);
 888
 889         while (!ts->stopped && get_pendown_state(ts)) {
 890
 891                 /* pen is down, continue with the measurement */
 892                 ads7846_read_state(ts);
 893
 894                 if (!ts->stopped)
 895                         ads7846_report_state(ts);
 896
 897                 wait_event_timeout(ts->wait, ts->stopped,
 898                                    msecs_to_jiffies(TS_POLL_PERIOD));
 899         }
 900
 901         if (ts->pendown) {
 902                 struct input_dev *input = ts->input;
 903
 904                 input_report_key(input, BTN_TOUCH, 0);
 905                 input_report_abs(input, ABS_PRESSURE, 0);
 906                 input_sync(input);
 907
 908                 ts->pendown = false;
 909                 dev_vdbg(&ts->spi->dev, "UP\n");
 910         }
 911
 912         return IRQ_HANDLED;
 913 }
 914
 915 #ifdef CONFIG_PM_SLEEP
 916 static int ads7846_suspend(struct device *dev)
 917 {
 918         struct ads7846 *ts = dev_get_drvdata(dev);
 919
 920         mutex_lock(&ts->lock);
 921
 922         if (!ts->suspended) {
 923
 924                 if (!ts->disabled)
 925                         __ads7846_disable(ts);
 926
 927                 if (device_may_wakeup(&ts->spi->dev))
 928                         enable_irq_wake(ts->spi->irq);
 929
 930                 ts->suspended = true;
 931         }
 932
 933         mutex_unlock(&ts->lock);
 934
 935         return 0;
 936 }
 937
 938 static int ads7846_resume(struct device *dev)
 939 {
 940         struct ads7846 *ts = dev_get_drvdata(dev);
 941
 942         mutex_lock(&ts->lock);
 943
 944         if (ts->suspended) {
 945
 946                 ts->suspended = false;
 947
 948                 if (device_may_wakeup(&ts->spi->dev))
 949                         disable_irq_wake(ts->spi->irq);
 950
 951                 if (!ts->disabled)
 952                         __ads7846_enable(ts);
 953         }
 954
 955         mutex_unlock(&ts->lock);
 956
 957         return 0;
 958 }
 959 #endif
 960
 961 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 962
 963 static int ads7846_setup_pendown(struct spi_device *spi,
 964                                            struct ads7846 *ts)
 965 {
 966         struct ads7846_platform_data *pdata = spi->dev.platform_data;
 967         int err;
 968
 969         /*
 970          * REVISIT when the irq can be triggered active-low, or if for some
 971          * reason the touchscreen isn't hooked up, we don't need to access
 972          * the pendown state.
 973          */
 974
 975         if (pdata->get_pendown_state) {
 976                 ts->get_pendown_state = pdata->get_pendown_state;
 977         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 978
 979                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 980                                        "ads7846_pendown");
 981                 if (err) {
 982                         dev_err(&spi->dev,
 983                                 "failed to request/setup pendown GPIO%d: %d\n",
 984                                 pdata->gpio_pendown, err);
 985                         return err;
 986                 }
 987
 988                 ts->gpio_pendown = pdata->gpio_pendown;
 989
 990                 if (pdata->gpio_pendown_debounce)
 991                         gpio_set_debounce(pdata->gpio_pendown,
 992                                           pdata->gpio_pendown_debounce);
 993         } else {
 994                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 995                 return -EINVAL;
 996         }
 997
 998         return 0;
 999 }
1000
1001 /*
1002  * Set up the transfers to read touchscreen state; this assumes we
1003  * use formula #2 for pressure, not #3.
1004  */
1005 static void ads7846_setup_spi_msg(struct ads7846 *ts,
1006                                 const struct ads7846_platform_data *pdata)
1007 {
1008         struct spi_message *m = &ts->msg[0];
1009         struct spi_transfer *x = ts->xfer;
1010         struct ads7846_packet *packet = ts->packet;
1011         int vref = pdata->keep_vref_on;
1012
1013         if (ts->model == 7873) {
1014                 /*
1015                  * The AD7873 is almost identical to the ADS7846
1016                  * keep VREF off during differential/ratiometric
1017                  * conversion modes.
1018                  */
1019                 ts->model = 7846;
1020                 vref = 0;
1021         }
1022
1023         ts->msg_count = 1;
1024         spi_message_init(m);
1025         m->context = ts;
1026
1027         if (ts->model == 7845) {
1028                 packet->read_y_cmd[0] = READ_Y(vref);
1029                 packet->read_y_cmd[1] = 0;
1030                 packet->read_y_cmd[2] = 0;
1031                 x->tx_buf = &packet->read_y_cmd[0];
1032                 x->rx_buf = &packet->tc.y_buf[0];
1033                 x->len = 3;
1034                 spi_message_add_tail(x, m);
1035         } else {
1036                 /* y- still on; turn on only y+ (and ADC) */
1037                 packet->read_y = READ_Y(vref);
1038                 x->tx_buf = &packet->read_y;
1039                 x->len = 1;
1040                 spi_message_add_tail(x, m);
1041
1042                 x++;
1043                 x->rx_buf = &packet->tc.y;
1044                 x->len = 2;
1045                 spi_message_add_tail(x, m);
1046         }
1047
1048         /*
1049          * The first sample after switching drivers can be low quality;
1050          * optionally discard it, using a second one after the signals
1051          * have had enough time to stabilize.
1052          */
1053         if (pdata->settle_delay_usecs) {
1054                 x->delay_usecs = pdata->settle_delay_usecs;
1055
1056                 x++;
1057                 x->tx_buf = &packet->read_y;
1058                 x->len = 1;
1059                 spi_message_add_tail(x, m);
1060
1061                 x++;
1062                 x->rx_buf = &packet->tc.y;
1063                 x->len = 2;
1064                 spi_message_add_tail(x, m);
1065         }
1066
1067         ts->msg_count++;
1068         m++;
1069         spi_message_init(m);
1070         m->context = ts;
1071
1072         if (ts->model == 7845) {
1073                 x++;
1074                 packet->read_x_cmd[0] = READ_X(vref);
1075                 packet->read_x_cmd[1] = 0;
1076                 packet->read_x_cmd[2] = 0;
1077                 x->tx_buf = &packet->read_x_cmd[0];
1078                 x->rx_buf = &packet->tc.x_buf[0];
1079                 x->len = 3;
1080                 spi_message_add_tail(x, m);
1081         } else {
1082                 /* turn y- off, x+ on, then leave in lowpower */
1083                 x++;
1084                 packet->read_x = READ_X(vref);
1085                 x->tx_buf = &packet->read_x;
1086                 x->len = 1;
1087                 spi_message_add_tail(x, m);
1088
1089                 x++;
1090                 x->rx_buf = &packet->tc.x;
1091                 x->len = 2;
1092                 spi_message_add_tail(x, m);
1093         }
1094
1095         /* ... maybe discard first sample ... */
1096         if (pdata->settle_delay_usecs) {
1097                 x->delay_usecs = pdata->settle_delay_usecs;
1098
1099                 x++;
1100                 x->tx_buf = &packet->read_x;
1101                 x->len = 1;
1102                 spi_message_add_tail(x, m);
1103
1104                 x++;
1105                 x->rx_buf = &packet->tc.x;
1106                 x->len = 2;
1107                 spi_message_add_tail(x, m);
1108         }
1109
1110         /* turn y+ off, x- on; we'll use formula #2 */
1111         if (ts->model == 7846) {
1112                 ts->msg_count++;
1113                 m++;
1114                 spi_message_init(m);
1115                 m->context = ts;
1116
1117                 x++;
1118                 packet->read_z1 = READ_Z1(vref);
1119                 x->tx_buf = &packet->read_z1;
1120                 x->len = 1;
1121                 spi_message_add_tail(x, m);
1122
1123                 x++;
1124                 x->rx_buf = &packet->tc.z1;
1125                 x->len = 2;
1126                 spi_message_add_tail(x, m);
1127
1128                 /* ... maybe discard first sample ... */
1129                 if (pdata->settle_delay_usecs) {
1130                         x->delay_usecs = pdata->settle_delay_usecs;
1131
1132                         x++;
1133                         x->tx_buf = &packet->read_z1;
1134                         x->len = 1;
1135                         spi_message_add_tail(x, m);
1136
1137                         x++;
1138                         x->rx_buf = &packet->tc.z1;
1139                         x->len = 2;
1140                         spi_message_add_tail(x, m);
1141                 }
1142
1143                 ts->msg_count++;
1144                 m++;
1145                 spi_message_init(m);
1146                 m->context = ts;
1147
1148                 x++;
1149                 packet->read_z2 = READ_Z2(vref);
1150                 x->tx_buf = &packet->read_z2;
1151                 x->len = 1;
1152                 spi_message_add_tail(x, m);
1153
1154                 x++;
1155                 x->rx_buf = &packet->tc.z2;
1156                 x->len = 2;
1157                 spi_message_add_tail(x, m);
1158
1159                 /* ... maybe discard first sample ... */
1160                 if (pdata->settle_delay_usecs) {
1161                         x->delay_usecs = pdata->settle_delay_usecs;
1162
1163                         x++;
1164                         x->tx_buf = &packet->read_z2;
1165                         x->len = 1;
1166                         spi_message_add_tail(x, m);
1167
1168                         x++;
1169                         x->rx_buf = &packet->tc.z2;
1170                         x->len = 2;
1171                         spi_message_add_tail(x, m);
1172                 }
1173         }
1174
1175         /* power down */
1176         ts->msg_count++;
1177         m++;
1178         spi_message_init(m);
1179         m->context = ts;
1180
1181         if (ts->model == 7845) {
1182                 x++;
1183                 packet->pwrdown_cmd[0] = PWRDOWN;
1184                 packet->pwrdown_cmd[1] = 0;
1185                 packet->pwrdown_cmd[2] = 0;
1186                 x->tx_buf = &packet->pwrdown_cmd[0];
1187                 x->len = 3;
1188         } else {
1189                 x++;
1190                 packet->pwrdown = PWRDOWN;
1191                 x->tx_buf = &packet->pwrdown;
1192                 x->len = 1;
1193                 spi_message_add_tail(x, m);
1194
1195                 x++;
1196                 x->rx_buf = &packet->dummy;
1197                 x->len = 2;
1198         }
1199
1200         CS_CHANGE(*x);
1201         spi_message_add_tail(x, m);
1202 }
1203
1204 static int ads7846_probe(struct spi_device *spi)
1205 {
1206         struct ads7846 *ts;
1207         struct ads7846_packet *packet;
1208         struct input_dev *input_dev;
1209         struct ads7846_platform_data *pdata = spi->dev.platform_data;
1210         unsigned long irq_flags;
1211         int err;
1212
1213         if (!spi->irq) {
1214                 dev_dbg(&spi->dev, "no IRQ?\n");
1215                 return -ENODEV;
1216         }
1217
1218         if (!pdata) {
1219                 dev_dbg(&spi->dev, "no platform data?\n");
1220                 return -ENODEV;
1221         }
1222
1223         /* don't exceed max specified sample rate */
1224         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1225                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1226                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1227                 return -EINVAL;
1228         }
1229
1230         /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1231          * that even if the hardware can do that, the SPI controller driver
1232          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1233          */
1234         spi->bits_per_word = 8;
1235         spi->mode = SPI_MODE_0;
1236         err = spi_setup(spi);
1237         if (err < 0)
1238                 return err;
1239
1240         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1241         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1242         input_dev = input_allocate_device();
1243         if (!ts || !packet || !input_dev) {
1244                 err = -ENOMEM;
1245                 goto err_free_mem;
1246         }
1247
1248         spi_set_drvdata(spi, ts);
1249
1250         ts->packet = packet;
1251         ts->spi = spi;
1252         ts->input = input_dev;
1253         ts->vref_mv = pdata->vref_mv;
1254         ts->swap_xy = pdata->swap_xy;
1255
1256         mutex_init(&ts->lock);
1257         init_waitqueue_head(&ts->wait);
1258
1259         ts->model = pdata->model ? : 7846;
1260         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1261         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1262         ts->pressure_max = pdata->pressure_max ? : ~0;
1263
1264         if (pdata->filter != NULL) {
1265                 if (pdata->filter_init != NULL) {
1266                         err = pdata->filter_init(pdata, &ts->filter_data);
1267                         if (err < 0)
1268                                 goto err_free_mem;
1269                 }
1270                 ts->filter = pdata->filter;
1271                 ts->filter_cleanup = pdata->filter_cleanup;
1272         } else if (pdata->debounce_max) {
1273                 ts->debounce_max = pdata->debounce_max;
1274                 if (ts->debounce_max < 2)
1275                         ts->debounce_max = 2;
1276                 ts->debounce_tol = pdata->debounce_tol;
1277                 ts->debounce_rep = pdata->debounce_rep;
1278                 ts->filter = ads7846_debounce_filter;
1279                 ts->filter_data = ts;
1280         } else {
1281                 ts->filter = ads7846_no_filter;
1282         }
1283
1284         err = ads7846_setup_pendown(spi, ts);
1285         if (err)
1286                 goto err_cleanup_filter;
1287
1288         if (pdata->penirq_recheck_delay_usecs)
1289                 ts->penirq_recheck_delay_usecs =
1290                                 pdata->penirq_recheck_delay_usecs;
1291
1292         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1293
1294         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1295         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1296
1297         input_dev->name = ts->name;
1298         input_dev->phys = ts->phys;
1299         input_dev->dev.parent = &spi->dev;
1300
1301         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1302         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1303         input_set_abs_params(input_dev, ABS_X,
1304                         pdata->x_min ? : 0,
1305                         pdata->x_max ? : MAX_12BIT,
1306                         0, 0);
1307         input_set_abs_params(input_dev, ABS_Y,
1308                         pdata->y_min ? : 0,
1309                         pdata->y_max ? : MAX_12BIT,
1310                         0, 0);
1311         input_set_abs_params(input_dev, ABS_PRESSURE,
1312                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1313
1314         ads7846_setup_spi_msg(ts, pdata);
1315
1316         ts->reg = regulator_get(&spi->dev, "vcc");
1317         if (IS_ERR(ts->reg)) {
1318                 err = PTR_ERR(ts->reg);
1319                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1320                 goto err_free_gpio;
1321         }
1322
1323         err = regulator_enable(ts->reg);
1324         if (err) {
1325                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1326                 goto err_put_regulator;
1327         }
1328
1329         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1330         irq_flags |= IRQF_ONESHOT;
1331
1332         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1333                                    irq_flags, spi->dev.driver->name, ts);
1334         if (err && !pdata->irq_flags) {
1335                 dev_info(&spi->dev,
1336                         "trying pin change workaround on irq %d\n", spi->irq);
1337                 irq_flags |= IRQF_TRIGGER_RISING;
1338                 err = request_threaded_irq(spi->irq,
1339                                   ads7846_hard_irq, ads7846_irq,
1340                                   irq_flags, spi->dev.driver->name, ts);
1341         }
1342
1343         if (err) {
1344                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1345                 goto err_disable_regulator;
1346         }
1347
1348         err = ads784x_hwmon_register(spi, ts);
1349         if (err)
1350                 goto err_free_irq;
1351
1352         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1353
1354         /*
1355          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1356          * the touchscreen, in case it's not connected.
1357          */
1358         if (ts->model == 7845)
1359                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1360         else
1361                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1362
1363         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1364         if (err)
1365                 goto err_remove_hwmon;
1366
1367         err = input_register_device(input_dev);
1368         if (err)
1369                 goto err_remove_attr_group;
1370
1371         device_init_wakeup(&spi->dev, pdata->wakeup);
1372
1373         return 0;
1374
1375  err_remove_attr_group:
1376         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1377  err_remove_hwmon:
1378         ads784x_hwmon_unregister(spi, ts);
1379  err_free_irq:
1380         free_irq(spi->irq, ts);
1381  err_disable_regulator:
1382         regulator_disable(ts->reg);
1383  err_put_regulator:
1384         regulator_put(ts->reg);
1385  err_free_gpio:
1386         if (!ts->get_pendown_state)
1387                 gpio_free(ts->gpio_pendown);
1388  err_cleanup_filter:
1389         if (ts->filter_cleanup)
1390                 ts->filter_cleanup(ts->filter_data);
1391  err_free_mem:
1392         input_free_device(input_dev);
1393         kfree(packet);
1394         kfree(ts);
1395         return err;
1396 }
1397
1398 static int ads7846_remove(struct spi_device *spi)
1399 {
1400         struct ads7846 *ts = spi_get_drvdata(spi);
1401
1402         device_init_wakeup(&spi->dev, false);
1403
1404         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1405
1406         ads7846_disable(ts);
1407         free_irq(ts->spi->irq, ts);
1408
1409         input_unregister_device(ts->input);
1410
1411         ads784x_hwmon_unregister(spi, ts);
1412
1413         regulator_disable(ts->reg);
1414         regulator_put(ts->reg);
1415
1416         if (!ts->get_pendown_state) {
1417                 /*
1418                  * If we are not using specialized pendown method we must
1419                  * have been relying on gpio we set up ourselves.
1420                  */
1421                 gpio_free(ts->gpio_pendown);
1422         }
1423
1424         if (ts->filter_cleanup)
1425                 ts->filter_cleanup(ts->filter_data);
1426
1427         kfree(ts->packet);
1428         kfree(ts);
1429
1430         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1431
1432         return 0;
1433 }
1434
1435 static struct spi_driver ads7846_driver = {
1436         .driver = {
1437                 .name   = "ads7846",
1438                 .owner  = THIS_MODULE,
1439                 .pm     = &ads7846_pm,
1440         },
1441         .probe          = ads7846_probe,
1442         .remove         = ads7846_remove,
1443 };
1444
1445 module_spi_driver(ads7846_driver);
1446
1447 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1448 MODULE_LICENSE("GPL");
1449 MODULE_ALIAS("spi:ads7846");